I had same problem on my 3 door a couple of years ago, eventually it gave up all together, took a long time to solve it but mine ended up being a fault in the phase sensor that was breaking down when it got hot, I fitted a new one gapped and timed correctly and it fired up, no issues since but could be any sensor causing problems, or even the loom or connections, just try cleaning and checking gaps on crank and phase sensor then check all plugs and loom connections.